**Core Concept**
Lymph nodes have a distinct histological structure with zones such as the cortex, medulla, and sinuses. The white pulp is involved in immune responses, while the red pulp is a feature of the spleen, not lymph nodes.

**Why the Correct Answer is Right**
Lymph nodes contain a **white pulp** (involved in immune surveillance) and a **medulla** (housing medullary cords and sinuses), with **subcapsular sinuses** and **both afferent and efferent lymphatic vessels**. However, **red pulp** is a specialized structure found only in the spleen, where it filters old or damaged red blood cells. Lymph nodes do not have red pulp.

**Why Each Wrong Option is Incorrect**
Option A: The **subcapsular sinus** is present and acts as a filter for lymph entering the node.
Option B: Both **afferent and efferent lymphatic vessels** are present — afferent brings lymph in, efferent carries it out.
Option C: **Cortex and medulla** are both present — cortex contains lymphoid follicles, medulla contains medullary cords and sinuses.
Option D: **Red pulp is absent** in lymph nodes; this is the key error — it is a spleen-specific feature.

**Clinical Pearl / High-Yield Fact**
Remember: **Spleen has red pulp** (filters RBCs), **lymph nodes have white pulp** (immune defense). Never confuse the two — red pulp is a spleen feature only.

✓ Correct Answer: D. Red pulp and White pulp are present